ACR Electronics

ACR Electronics marine safety equipment, including handheld VHF radios, searchlights and their remote controllers, personal locator beacons (Pathfinder PRO), and EPIRB batteries.

Personal locator beacons and EPIRBs work differently from a VHF radio or satellite phone — they transmit a one-way distress signal with GPS position to search-and-rescue satellites rather than supporting two-way communication, so they're a backup for emergencies specifically, not a general communication device.

Registering a PLB or EPIRB with NOAA (in the US) is required so search-and-rescue services can identify you — an unregistered beacon still transmits, but responders have no owner information attached to it.